The present invention relates to air conditioners, and in particular, to an air conditioner that employs a flammable refrigerant (including slightly flammable refrigerant, this holding true throughout this specification).
In recent years, there has been proposed an air conditioner that employs a flammable refrigerant of R32 or the like as an alternative refrigerant substituting for R22. In the air conditioner that employs this kind of flammable refrigerant, there is concern about an accident such that the flammable refrigerant leaks from the inside of an indoor unit or a refrigerant pipe (connecting pipe) connected to the indoor unit to the outside, causing a fire or generating a toxic gas due to deficiency of oxygen and thermal decomposition (referred to as an xe2x80x9caccident of a fire or the likexe2x80x9d).
However, it is difficult to say that conventional air conditioners have taken sufficient measures against the case of flammable refrigerant leak.
Accordingly, the object of this invention is to provide an air conditioner capable of preventing the accident of a fire or the like even in the case of flammable refrigerant leak.
In order to achieve the above-mentioned object, the present invention provides an air conditioner employing a flammable refrigerant, comprising a sensor that is provided on an external surface of an indoor unit and detects a flammable refrigerant gas.
The air conditioner of the present invention is provided with the sensor that is provided on the external surface of the indoor unit and detects the flammable refrigerant gas. Therefore, when the flammable refrigerant leaks from the refrigerant pipe (connecting pipe) connected to the indoor unit into a room or when the flammable refrigerant that has leaked inside the indoor unit flows to the outside of the indoor unit through a gap of the casing, then the refrigerant that has leaked and gasified can be detected by the sensor. Therefore, it is enabled to issue a warning based on the output of the sensor or shut off the refrigerant circuit. As a result, the accident of a fire or the like can be prevented.
In order to achieve the above-mentioned object, the present invention provides an air conditioner, which is provided with a indoor unit housing a heat exchanger and a fan inside its casing that has an inlet port and an outlet port, rotates the fan and flows the flammable refrigerant through the heat exchanger during operation, performing heat exchange between air taken into the casing through the inlet port and the flammable refrigerant, and blows out the air that has undergone the heat exchange to the inside of a room through the outlet port, comprising a sensor that is provided on an external surface of the casing and detects a flammable refrigerant gas, and a control section for executing control to rotate the fan when the sensor detects the flammable refrigerant gas.
The air conditioner of the present invention is provided with the sensor that is provided on the external surface of the casing of the indoor unit and detects the flammable refrigerant gas. Therefore, when the flammable refrigerant leaks from the refrigerant pipe (connecting pipe) connected to the indoor unit into a room or when the flammable refrigerant that has leaked inside the indoor unit flows to the outside of the indoor unit through a gap of the casing, then the refrigerant that has leaked and gasified can be detected by the sensor. When the sensor detects the flammable refrigerant gas, the control section executes control to rotate the fan. By this operation, the refrigerant gas can be diffused to have a concentration not higher than the lower flammability limit concentration by virtue of an air flow generated by the rotation of the fan, i.e., a flow of air, which has been taken into the casing through the inlet port and blown out to the inside of the room through the outlet port. As a result, the accident of a fire or the like can be prevented.
Moreover, the fan has originally been provided for the indoor unit, and the hardware that constitutes the control section can be made common to the one that has originally been provided for the operation of the air conditioner. Therefore, in applying the present invention to an ordinary air conditioner, no particular cost increase is caused.
In an embodiment of the present invention, the indoor unit is of a floor type, and the sensor is provided in a lower portion of the indoor unit.
The flammable refrigerant of R32 or the like has the property that it is heavier than air. Therefore, when the indoor unit is placed on a floor, the flammable refrigerant that has leaked from the refrigerant pipe (connecting pipe) connected to the indoor unit into a room and the flammable refrigerant that has leaked inside the indoor unit and flowed out of the indoor unit through the gap of the casing tend to be collected on the indoor floor. In this case, according to the air conditioner of this one embodiment, the sensor is provided in a lower portion of the indoor unit. Therefore, the flammable refrigerant gas collected on the indoor floor can reliably be detected by the sensor. Therefore, the accident of a fire or the like can reliably be prevented. Moreover, if the control section executes the control to rotate the fan when the sensor detects the flammable refrigerant gas, then the flammable refrigerant gas collected on the indoor floor is effectively diffused by the air flow generated by the rotation of the fan, i.e., the flow of air, which has been taken into the casing through the inlet port and blown out to the inside of the room through the outlet port, and is made to have a concentration not higher than the lower flammability limit concentration. Therefore, the accident of a fire or the like can reliably be prevented.
In an embodiment of the present invention, the indoor unit is of a ceiling recessed type, and the sensor is provided in a lower portion that belongs to the indoor unit and faces the reverse side of ceiling board.
As described above, the flammable refrigerant of R32 or the like has the property that it is heavier than air. Therefore, when the indoor unit is set in a ceiling, the flammable refrigerant that has leaked from the refrigerant pipe (connecting pipe) connected to the indoor unit into the room and the flammable refrigerant that has leaked inside the indoor unit and flowed to the outside of the indoor unit through the gap of the casing are possibly collected in the roof space. In this case, according to the air conditioner of this one embodiment, the sensor is provided in the lower portion that belongs to the indoor unit and faces the roof space. Therefore, the flammable refrigerant gas collected in the roof space can reliably be detected by the sensor. Therefore, the accident of a fire or the like can reliably be prevented.
In an embodiment of the present invention, the sensor is arranged in an opening located in a lower portion of the casing of the indoor unit and detects a flammable refrigerant gas leaked to the outside and inside of the indoor unit.
As described hereinabove, the flammable refrigerant of R32 or the like has the property that it is heavier than air. Therefore, the flammable refrigerant that has leaked inside the indoor unit tends to be collected in the lower portion of the indoor unit. In this case, according to the air conditioner of the fourth inventive aspect, the sensor is arranged at the opening located in the lower portion of the casing of the indoor unit and detects the flammable refrigerant gas that has leaked to the outside and inside of the indoor unit. Therefore, not only the flammable refrigerant gas that has leaked to the outside of the indoor unit but also the flammable refrigerant gas that has leaked inside the indoor unit can reliably be detected by the sensor. Therefore, the accident of a fire or the like can reliably be prevented. Moreover, if the control section executes the control to rotate the fan when the sensor detects the flammable refrigerant gas, then the flammable refrigerant gas leaked inside the indoor unit is effectively diffused by the air flow generated by the rotation of the fan, i.e., the flow of air, which has been taken into the casing through the inlet port and blown out to the inside of a room through the outlet port, and is made to have a concentration not higher than the lower flammability limit concentration. Therefore, the accident of a fire or the like can reliably be prevented.
Moreover, the flammable refrigerant gas that has leaked from one indoor unit and its surroundings can reliably be detected by the sensor. Therefore, one indoor unit is permitted to have only one flammable refrigerant gas detection sensor in order to prevent the accident of a fire or the like, and cost increase can be suppressed. To provide sensors for detecting the refrigerant gas in the portions where refrigerant leak possibly occurs, or, for example, in each of the connecting portions of the refrigerant pipes and the heat exchanger inside the indoor unit leads to an increase in the number of sensors and further cost increase.
In an embodiment of the present invention, the air conditioner comprises means for issuing a warning when the sensor detects the flammable refrigerant gas.
In the air conditioner of this embodiment, a warning is issued when the sensor detects the flammable refrigerant gas. Therefore, the user can perceive the leak of the flammable refrigerant and take the measures of ventilating the room, calling serviceman for repair and the like.
In an embodiment of the present invention, the air conditioner comprises a control section for executing control to stop operation of a refrigerant circuit of the air conditioner when the sensor detects the flammable refrigerant gas.
In the air conditioner of this embodiment, the control section executes the control to stop the operation of the refrigerant circuit of this air conditioner when the sensor detects the flammable refrigerant gas. Therefore, the refrigerant circuit is shut off by the valve that exists in the refrigerant circuit, and the leak of flammable refrigerant is restrained. The flammable refrigerant remaining in the refrigerant pipes flows to a certain extent from the leak portion of the trouble, but the outflow is reduced since no more pressure is applied.
In an embodiment of the present invention, the flammable refrigerant is R32 or a mixed refrigerant that contains 70 percent by weight of R32, or propane or a mixed refrigerant that contains propane.
The refrigerant R32 or a mixed refrigerant that contains 70 percent by weight of R32, or propane or a mixed refrigerant that contains propane are regarded as promising alternative refrigerants substituting for R22. According to the air conditioner of this one embodiment, the accident of a fire or the like can be prevented when R32 or a mixed refrigerant that contains 70 percent by weight of R32, or propane or a mixed refrigerant that contains 70 percent by weight of propane, which are regarded as promising alternative refrigerants substituting for R22, leaks.